Conventional conferencing services such as Push-To-Video (PTV) services permit an inviting user to set up a conference call, inviting other users to join. Typically, these conference calls are set up utilizing the internet and one of numerous internet protocols (IP). A Session Initiation Protocol (SIP) works in concert with other IPs by enabling user entities to discover one another and to agree on a characterization of a session they would like to share. SIP is an application-layer control protocol that can establish, modify, and terminate multimedia sessions (conferences). SIP can also invite participants to already existing sessions, such as multicast conferences.
Fundamentally the conference setup is based on an offer/answer model that requires agreeing on a common set of media modes and codec characteristics before starting a call. The common set of media modes of the call could be PTV Stream (audio or video streamed asynchronously to the participants in the packet domain), PTV Chat (audio and video streamed synchronously to the participants in the packet domain), or PTT (audio only). If the participants do not agree on the same number of media and common codec, then the conference call will not be successful. Additionally, if a participant needs to sign off of the audio services (such as going to mute in a high noise environment) or the video services (to conserve bandwidth or moving into an area which does not support the video), the participant's only option is to resign from the call.
Thus, what is needed is a method and apparatus for permitting mixed mode participants on a multimedia conference call. In addition, what is needed is a method and apparatus for allowing participants in such a multi-mode conference call to upgrade and/or downgrade participation in the multi-mode conference call by adding or resigning from modes of the conference call without resigning from the conference call. Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description of the invention and the appended claims, taken in conjunction with the accompanying drawings and this background of the invention.